1) Field of the Disclosure
The disclosure relates generally to systems and methods for measuring oxygen concentration in fuel tanks, and more specifically, to oxygen analysis systems and methods for measuring, monitoring and recording oxygen concentration in aircraft fuel tanks.
2) Description of Related Art
Nitrogen generation systems (“NGS”) may be utilized to reduce the combustibility of aircraft fuel tanks. An NGS produces nitrogen, which is fed into the fuel tanks, and oxygen enriched air as a byproduct. Prior NGS certification testing of an NGS was initially performed with a measurement system supplied by the Federal Aviation Administration (FAA) Technical Center using a system known as “OBOAS” (On-Board Oxygen Analysis System). OBOAS was based on an electrochemical sensor technology. OBOAS worked but required unacceptably high maintenance and operator intervention to ensure adequate data quality. Moreover, OBOAS was not adequately efficient to support the rapid pace of a major test program.
Other known systems and methods were also used for NGS certification testing. One such known system used a single-channel, off-the-shelf oxygen sensor analyzer on select programs where only a single measurement was required at the NGS air separation module (ASM) exit.
However, in later generation aircraft, the NGS applies to the main fuel tanks as well as the center fuel tank, and requires measurements at 22 locations, including 7 measurements in the left main fuel tank, 8 measurements in the center fuel tank, and 6 measurements in the right main fuel tank, plus one measurement at the NGS ASM exit. One known system allowed for 8 measurements. However, additional manual valves needed to be added to permit measurements at the measurement locations. This involved having to manually track valve positions to understand which location was being measured. Moreover, such known system was a manually operated and manually switched system, which was unduly complex and expensive.
Moreover, such prior known systems and methods may require an increased level of monitoring and a high degree of temperature stability, which would not be suitable for such later generation aircraft. Thus, such prior known systems and methods would not be adequate for NGS certification for such later generation aircraft requiring measurements at 22 locations.
Accordingly, what is needed is an improved oxygen analysis system and method for measuring, monitoring and recording oxygen concentration in aircraft fuel tanks that provide advantages over known systems and methods.